WASHINGTON -- Former Democratic presidential candidate Paul E. Tsongas and retiring Republican Sen. Warren B. Rudman endorsed a campaign yesterday to force all presidential and congressional candidates to sign a pledge to resign if the fiscal 1992 budget is not halved by 1996.

The veteran deficit campaigners will launch their own bipartisan deficit-reduction movement next month, but yesterday they threw their political weight behind the pledge campaign being launched here by a group of young activists.

In an echo of his primary campaign message, Mr. Tsongas warned, "This country is headed toward generational warfare. It will eventually pit young against old in a kind of bitter division this country has never seen before."

Jon Cowan, 27, a former aide to a Democratic congressman from California and a co-founder of the "Lead -- or Leave" pledge movement, said all candidates for federal office, including President Bush and Democratic challenger Bill Clinton, will be asked to sign the pledge.

"We think that kind of collective accountability is the only way we are going to get things done," he said.

Noting that interest payments on the $4 trillion national debt were now $200 billion a year, Mr. Cowan said, "We are being burdened with that. It is as if our parents had taken out a credit card with our name on it and they were charging the bill to us, which is fairly scandalous."

The other founder of the movement, Rob Nelson, 28, a former fund-raiser for liberal Democratic causes, called for entitlement programs including Social Security, Medicaid and Medicare to be means-tested, defense spending to be cut further, and the rich to be taxed more.

Mr. Nelson said the 18-to-30 age group would not be overlooked or "silenced," adding, "We are not going away, and this problem is not going away. We are not the generation who has spent $4 trillion in debt. We are the generation that is going to pay for it."

While both the Bush and Clinton economic plans pay lip service to the urgent need for deficit reduction, neither of them propose any major reduction. Both are more focused on economic growth through either tax breaks or public spending, which actually risks adding to the deficit.

Gov. Clinton issued a statement yesterday saying his economic plan would cut the deficit in half by 1996, but a spokesman said he would not sign the pledge.

In his statement he said: "As president I expect to be judged on my record." He pointed out that Mr. Bush also had a record -- of being in administrations that quadrupled the national debt over 12 years and double the deficit over four.

There was no immediate comment from the White House.

Congress has operated under spending ceilings since the 1990 budget agreement, but earlier this year it defeated a move to pass a balanced budget amendment.

The fiscal 1992 deficit is projected by the Bush administration to be $333.5 billion, down from the original estimate of $400 billion largely because of Congress' refusal to earmark more funds for the savings and loan bailout.

The pledge would entail bringing it down to below $167 billion over the next four years.

Mr. Tsongas said both Republicans and Democrats were responsible for the deficit legacy of the past decade.

"The fact is that what you and I looked forward to as young people is not going to be available for this generation, and the implications of that are enormous," the former Massachusetts senator said.